Electrical system



Aug. 1950 A. H. DICKINSON ETAL 2,517,987

ELECTRICAL SYSTEM Filed March 1, 1946 2 Sheets-Sheet 1 FIG. i.

INVENTORS A. If alarm/501v BEAMBROS/O ATTORNEY 1950 A. H. mcKmsoN srm. 2,517,987

ELECTRICAL SYSTEM 2 Sheets$heet 2 Filed March 1, 1946 A h- DICKINSON BfEYi/VB HOS/0 was Aug. 8, 1950 UNITED STATES PATENT OFFICE ELEQTRICAL SYSTEM I Arthur H. Dickinson, Greenwich, Conn, and

Biagio F. Ambrosio, Long Island City, N. 1 assignors to International Business Machines Corporation, New York, N. Y., a corporation of New York- Application March 1, 1946, Serial No. 651,268

3 Claims. (Cl. 16115) G! 5. This invention relates to an electrical system making measurements, such as elapsed time measurements or the like.

an object of the invention is to provide an electrical system in which a cathode ray tube is controlled to produce a traveling index trace.

An object of the invention is to control cathode ray means to indicate elapsed time.

An object of the invention is to control cathode ray means to measure elapsed time between two distinct operations.

an object of the invention is to modulate the amplitude of constant frequency oscillations in accordance with the variable phenomenon; time, for example, and to control remote electrical means and according to such amplitudemodulated oscillations.

Other object of the invention will be pointed in the following description and claims and ustrated in the accompanying drawings, which sclose, by way of examples, the principle of the vention and the best mode, which has been contemplated, of applying that principle.

" "he drawings:

Fig. is a front view, in full scale, of a portion an indicator unit which includes cathode ray eic sed time indicating means.

ng means used to control the formation of ind x traces on the cathode ray tubes.

S is a face view of a scanned pattern-disk, on the same scale as Fig. 2.

eis a front view, in full scale, of a timer 3 which is used to produce time-regulated avel oi the index traces on the cathode ray tube ens.

is a circuit diagram. say be mentioned that while the invention of general application to the measurement of ogressive efiects, it has been specifically applied the measurement of elapsed time following each of two distinct operations in setting up a pair of values. In Fig. 5, keys H and F represent keyboards for setting up these values, and contacts Ho and Pa represent contacts closed under control of the keyboards.

. 2 is a side view, on a reduced scale,

H is attached to the front of housing I by screws passing. freely through elongated slots 56 in the plate. This allows the indicator plate to be laterally adjusted to register its zero graduation line with the zero positions of index traces formed upper and lower scales, respectively adjoining the Referring now to Fig. 1, the housing In of the upper and lower right openings. Ehere are twenty-four graduations, each representing an increment of five seconds. Means are described later for producing travel of the index traces to the right as viewed in Fig. l) at the rate of one graduation every. five seconds. Travel of the index trace of tube 52H starts when a sc-called H operation is made. Similarly, travel of the index trace of tube HF starts with the setting up of an F operation. Thus. the time elapsing from the start of the H operation is measured in seconds by the position of the trace of tube HH and the elapsed time from the start of the F operation is given by the trace of tube i215, with respect to the graduations. The elapsed time between the startingof the H operation and the starting of the F operation is measured by the number of graduations intervening between the index traces produced by tubes iZI-I and HF. the example illustrated in Fig. l, the position of the trace produced by tube tZI-I indicates an elapsed time of 40 seconds from the start of an H operation, the position of the trace produced tube 22F indicates that seconds have elapsed since the start of an F" operation. The number of graduations intervening between the two index traces is, 7, representing an elapsed time of 35 seconds between the setting up of the H and "F operations, and the observer can note that the F operation leads the H operation by 35 seconds.

The means for producing the index traces on the screens of tubes 12 "and HF include scanning means for a pattern dis 28 (Figs. 2 and 3). The scanning means includes exciter lamp MY and a condenser lens and diaphragm system inside tube 232' for focusing a thin, concentrated beam of light radially across the annular track Y on the disk 20. The track has an irregular pattern of opaque portions, varying from maximum to minimum radial depth. The rest of the track is transparent, allowing light to pass to the photocell 2-IY. A motor (shown only in the circuit diagram, Fig. 5) continuously rotates disk 20. During rotation of the disk, the track permits varying portions of the beam of light to pass to the photocell. The configuration of the opaque portion of the track is such that the amount of light passed to the photocell during each revolution'of the pattern disk varies several times between two extremes. As will be brought out in the circuit description, the variation of light upon the photocell is utilized to vary the potentials across two deflection plates of each of the cathode ray tubes l2I-I and 12F in such manner that index traces are formed on the tube. It is understood that other suitable means than the scanning means and pattern disk provided herein may be used to control the potentials across the deflection plates for the purpose of forming index traces.

Fig. 4 shows the' front of a conventional timer motor TM which is driven by 60 cycle A. C. voltage. This motor is used to introduce a time factor into the travel of the index traces on the oathode ray tube screens. On the face of the motor is a circular, time scale, each graduation representing five seconds. A shaft 28 driven by ,the motor carries a pointer 21 for sweeping the time scale. A stop 28 is adjusted about the'shaft 25 to a desired position on the scale and then locked in this position. As shown, the stop 28 is' adjusted to the position on the scale indicating two and a fraction minutes. The home position of the pointer 21 is at then graduation line. When current is applied to the motor, it turns the shaft 26 and the pointer 21 through one graduation every five seconds. When the pointer strikes the stop 28, turning of shaft 26 is halted. As long as power remains on the motor, it holds the pointer 21 against the stop 28. When power is taken off the motor, an interior spring (not shown) restores the shaft 26 andpointer 21 to home position.

Referring now to the circuit diagram, Fig. 5, the apparatus receives power from a 60 cycle 110 v. A. C. source by connecting a plug 3U to the A. C. source outlet. Closure of a switch 3! applies the A. C. potential to lines 32 and 33. These lines connect to the input of a power pack 34 which produces different values of D. C. potential on its output lines 35, 31, and 38 with respect to the ground line 39. The closure of a switch it connects the lines 32 and 33 to the input of a rectifler unit 4| which includes a step-down transformer (not shown) and produces a reduced D. C. potential on its output. The output services the filament of the exciter lamp 223! (also see Fig. 2), rendering it incandescent. Lines 32 and 33 are connected upon closure of a switch 203 to the motor PM which drives the pattern disk 20 (also see Figs. 2 and 3). With the exciter lamp 22 lit, the rotating pattern disk passes varying amounts of light, depending on the configuration of the opaque portion of track Y (see Fig. 3), to the photocell Y.

The photocell 24Y is connected between D. C. line and a resistor 42Y which terminates at ground. Resistor 423? is coupled by a condenser Y to a resistor Y. The resistor Y is tapped by the control grid of a pentode 45Y. This pentode has its cathode connected to ground by a resistor 46Y and a shunting capacitor "Y. The

suppressor of 45Y is connected to its cathode. Y

The screen of 45Y is held at steady potential by connection to D. C. line 31 through a resistor NY and to ground through a condenser NY. A reand produces amplified variations in current flow through the pentode. These variations are transferred by a capacitor EZY to a resistor 683? which is tapped by the grids of a twin triode MY. The common cathode of 6153! connects to ground via a resistor 55Y which is shunts by an adjustable resistor 5EY. The anodes o EGY are com-" nected to D. C. line 31 via an inductor WY. With the foregoing arrangement, current flow through MY and the load inductor 5W varies according to the grid potential. The inductor 51Y is connected to ground via a resonant circuit compris= ing an inductor 58S! and capacitoreiiY and also is connected to ground via a circuit comprising capacitor MW and resistor MY.

ResistortZY servesas the input impedance of a transmission line (3332', impressing thereon the output of double triode Edit. It is seen that the plifled by tubes MY and ElYfor distant trans-- mission via line 83Y. Were not corrective provi= sions made, the varying potentials producm on resistor 62Y would be distorted during transmission by line 63Y. Both phase and frequency distortion would occur. Phase distortion is eliminated by leaving cathode resistors 55! and EitY of tube 54Y unshunted by capacitance. With this arrangement, tube 54W has applied thereto a certain amount of inverse feedback, which is controlled by the adjustment of resistor EiSY. The provision of inductor 51Y in the load circuit of tube 54Y eliminates a large proportion of the frequency distortion. Since the reactance of inductor 51Y increases with an increase in frequency, the load resistance of tube MY correspondingly increases. Accordingly, high frequency variations in potential of the control grid are peaked in the output circuit of the tube to overcome transmission line losses. This peaking effect is augmented by the resonant circuit which comprises inductor 58Y and capacitor EQY.

The current and voltage variations applied in the foregoing manner to line 633! control the production of vertical index traces on the screens of the cathode ray tubes RH and E25. Each cathode ray tube includes an indirectly heated cathode, a control grid G and coordinate pairs of deflection plates XR-XL and YU-YL. When the grid is above cut-01f potential, an electron beam is directed from the cathode to the screen. The vertical position of the beam on the screen is determined by the potentials across the deflection plates YU and YL and the horizontal position of the beam is determined by the potentials across the deflection plates 2m and KL. By rapidly, continually varying the potential difference between plates YL and YU, the beam will be deflected up and down rapidly to produce a vertical index trace on the screen. The potential across plates XR. and XL will be varied, in a manner described .later, in accordance with elapsed time to cause the index trace to travel horizontally across the screen. To allow the cathode ray indicator tubes to function, a switch NY is preliminarily closed to connect the A. C. lines 32 and 33 to the primaries of transformers 65F, SSH, and 66. The secondary of transformer 66 supplies heater voltage to the cathode ray tubes |2H and I215. The grids G of the tubes l 2H and HF are commonly connected to the arm of a potentiometer 61 which shunts biasing battery 68. By this means, the grid bias of the tubes itor MY and potentiometer HY. The arm .of'

potentiometer NY is coupled to D. C. line 35- by a capacitor l3 and resistor M. The junction of the capacitor 73 and resistor ll is connected to a wire l5 which has parallel connections to the deflection plates YL of tubes IIH and "F; It may be noted that the transmission of the varying voltages brought about by the scanning means is effected by line 53Y near ground potential and that the capacitor 13 and resistor 14 provide direct current isolation means when translating voltage variations from a low potential reference to a high potential reference. Potentiometer "HY determines the amplitude of the varying voltages transferred to plates YL of the cathode ray tubes. The companion plates YU connect to D. C. line 35. The foregoing arrangement produces potential differences across plates YL and YU of each tube whichvary rapidly between two extremes. Accordingly, a virtually continuous vertical index trace is formed on the screen of each cathode ray tube.

The means for causing the index traces to travel horizontally across the screens of tubes iZH and ill will now he explained. This means ininductors NH and SIH are the secondaries of a eludes the two timer motors TM shown in Fig. 4

and previously described. One of the timer motors is associated with the H section of the apparatus and the other with the F section. Each section includes an oscillator circuit for producing a thousand-cycle-per-second wave which is amplitude-modulated under control of the associated timer motor. Both sections are alike, so that only one need he explained in detail. Similar elements of both sections are numbered alike but diflerentiated by letters H and F.

=Ccnsidering the H section, the associated mo- 'sor operates through shaft 16 (see Fig. 4) to drive the wiper arm or a fine wire, quality potentiometer Sill-l. With shaft 26 in zero position, the wiper arm uncovers no resistance and is at ground potential. When the motor is brought into operation, shaft turns toward the stop 28 (Fig. 4) and drives the wiper arm to uncover an increasing, time-proportional extent of the resistance element of the potentiometer. The resistance element of, potentiometer 30H is coupled to oscillator means which applies a thousand-cycle-per-second wave of fixed amplitude to the upper end of the resistance element. The oscillator means includes a tube NH. The cathodereturn circuit of hill includes a resistor HE and a parallel capacitor 83H. A coupling circuit between the grid and cathode of 8 [H is comprised of an inductor ME and a parallel capacitor 85H. The fundamental oscillator frequency is derived from the tank circuit comprising inductor 86H and capacitor 31H. This circuit is tuned to the fundamental frequency at which the oscillator is to operate, which in this instance is chosen as approximately one thousand cycles per second. The anode of tube Bill is connected to D. C. line 33 by a resistor 88H and is coupled to its cathode by a stabilizing circuit comprising capacitor SSH and resistor Still .in series with each other and with an inductor NH and parallel capacitor 92H. it is seen that inductor "H is the primary and transformer. The aforementioned stabilizing circuit intermediate the anode and cathode of tube 84H acts to maintain the oscillator at a substantially constant frequency irrespective of voltage variations between D. C. line 38 and ground.

The output of oscillator tube 8iH is fed to a buffer tube. 93H by a capacitor MH and potentiometer 951-1. The arm of 35H connects to the grid of 93H which has a cathode return circuit by way of the resistor 32K and which has an anode connection to line 38 by way of resistor 96H. It is clear that once potentiometer 95H is set, the load on the oscillator circuit is fixed. The output of 93H is a 1000 cycle-persecond wave of proper amplitude which is applied by a capacitor 91H to the resistance element of potentiometer 80H. The arm of ME is connected to the grids of a double t iode 38H. The cathode of 98H has a purely resistive connection 39H to ground. Since this resistor is not shunted by reactance, an inverse feedback effect is produced which stabilizes the operation of tube 88H. The anodes of 98H commonly connect to line 38 by way of the primary of a transformer HIGH. The secondary or this transformer serves as the input impedance of a transmission line it ill.

As long as the timer motor "1M stays in home or zero position, the arm of potentiometer 30H is at ground potential, as are the grids of tube 38H. Under this condition, no part of the 1000 cycle pcr-second wave applied to 30H is transmitted to tube SSH and, hence, no change in potential occurs upon the transmission line iOlH. But as soon as the Ho contacts are closed, signifying the start of an H operation, motor TM connected to voltage lines 32 and 33 and set running. its shaft 28 (Fig. 2) advances the arm of potentiometer 30H to uncover resistance increasing progressively in accordance with the time clapsing from the start of the H operation. Accordingly, a progressively increasing proportion of the amplitude of the was cycle-per-second wave applied to ME is transferred the grids of double triode 98H. In response, the tube ESE and the load transformer HIGH transfer an amplified, amplitude-iriodulated 108 cycle-pcr-second wave to the transmission line iiJil-l.

. Similarly, the F oscillator functions to produce a 1000 cycle-per-second wave which is amplitudemodulateci under control of the timer-operated arm or the potentiometer 80F the start of an F operation. Tube 98F and its load transindex traces produced on the screens of cathode such means.

ray tubes HE and HF. The means for converting the modulated waves on lines i013 and EMF to travel of the index traces are similar, so that a detailed explanation need be given of only one Considering the H section, the line NIH is connected to the primary oia transformer 835E. This transformer is coupled through a full wave rectifier circuit to the deflection plateXL of tube 32H. The rectifier circuit includes double diode itGH. This receives heater potential from the secondary of transformer 651-1. The anodes of iilSH are connected to opposite ends of the secondary of 285E. The cathode of 16H is connected to the center tap of the secondary of transformer SSH and also connected via a load resistor iOlH, shunted by a capacitor 7 MOI-I, to the center tap of the secondary of the transformer IH. The center tap of I05H also connects to' the arm of a potentiometer IOSH which extends between D. C. line 35 and ground. A capacitor IIOH connects the arm of "191-1 to ground. The rectified direct current potential is transmitted by a wire IHH to the deflection plate XL of tube IZH. The companion deflection plate XR is connected to D. C. line 35.

As stated before, when the timer motor of the H section is at home position, there is no change in potential on the transmission line illlH. Accordingly, the transformer Ill-5H does not develop a. voltage and there is no voltage generated across the double diode HIGH and no change in potential across the resistor lOTI-I. Under this condition, the potential of deflection plate XL of tube IZH is determined solely by the setting of potentlometer I09H. It may be mentioned that the potentiometer IOBH is preliminarily adjusted to provide for a potential difference across plates XL and KR such as to maintain the index trace at the zero graduation line (Fig. 1).

produced by tube IZH is in zero indicating position.

As previously explained, when timer motor TM of the H section is placed in operation at the start of an H operation, a 1000 cycle-per-second wave of continuously increasing amplitude is produced and is applied to line IUIH. Transformer |05H applies this wave form to double diode IDSH whose rectifying action produces a direct current voltage of progressively increasing amplitude across its load resistor HllH. This direct current voltage is applied to the plate XL of tube IZH and opposes to a progressively increasing extent the initial potential of the plate XL. According, the index trace of tube iZH travels to the right (Fig. l) at a uniform rate in correspondence with the passage of time from the start of the H operation. The position of the trace with respect to the graduations on indicator plate M (Fig. 1) measures the elapsed time. Therefore, it is necessary to move the index trace to the right not merely in proportion to time but through such time-proportional incremental distances as are consonant with the calibration of the time scale on plate 14. Specificially, the index trace must move to the right from each graduation to the next in five seconds, or at a rate such as to sweep across the entire scale in 120 seconds. While the timer motor advances the arm of potentiometer 80H across equal incremental proportions of the resistance element of 80H in given time increments, it does not follow that the increase in potential upon the potentiometer arm as it advances across an incremental proportion of the resistance element has a fixed value. The value of such increase in potential depends on the magnitude of the potential applied by the tube 93H to the resistance element of 80H. In other words, the greater the amplitude of the 1000 cycle-per-second wave applied by tube 93H to the resistance element, the greater will be the incremental increase in potential upon the potentiometer arm as it sweeps an incremental proportion of the resistance element. A correspondingly greater increase in potential upon the plate XL of tube IZH and a resulting greater distance of travel of its index trace will occur in a fixed movement of time. Thus, if the amplitude of the 1000 cycleper-second wave applied by tube 93H to the potentiometer 80H be too great, the index trace will traverse the time scale on plate id in less than 120 seconds, but if the applied amplitude be too small, the index trace will traverse only a fraction of the scale in 120 seconds. It is neces- Thus, at zero elapsed time of operation H, the index trace sary, then, that the applied amplitude be such that the index trace will traverse the entire time scale in exactly 120 seconds. The proper applied amplitude is obtained by correct adjustment of the arm of the potentiometer 95H. Such adjustment provides for the proper proportion of the output of oscillator tube Bil-I to be impressed upon the grid of tube 93H. In turp tube 93H will develop the proper amplitude of the 1000 cycle-per-second wave which when transmitted to the resistance element of K will .control, through the intervening means, travel of the index trace of i2H at the rate demanded by the calibration of the scale on plate it.

In the same manner as explained for the H section, the F section when placed in operation produces amplitude-modulated oscillations which are transmitted by line IMF to transformer 75F. These oscillations are rectified by double diode 36F and the output applied to the plate XL of tube iZF. Adjustment of the potentiometer F provides for the correct rate of travel of the index trace of tube IZF to the right with respect to the scale on plate' as. It may be noted that tube I06F receives filament voltage from transformer 65F and that elements GdF, tiF, 93F, 95F, 80F, 93F, IO0F, IMF, I081? and 39F have the same functions as the correspondingly numbered elements relating to the H oscillator and rectifier sections.

The index trace on tube iZH or tube i2F may be restored to zero position before or after two minutes have elapsed by reopening contacts He or Fa, respectively. Upon the reopening of contacts Ha, for instance, the timer motor of the H section returns immediately to home position, as does the arm of potentiometer 00H. Thereupon, the arm of 80H and the grids of tube 98H again are at ground potential and this tube develops no voltage upon the transformer il'iflH. Accordingly, there is no voltage upon line [NH and tube HJBH does not apply any potential to plate XL of tube iZH. Thereupon the trace of tube IZH returns to its zero position.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. An electrical measuring system comprising a cathode ray tube including a cathode ray source, a screen, and coordinate pairs of deflection elements to direct the ray to desired positions on the screen, a circuit including a grid controlled amplifier tube having only a resistance element in its cathode circuit, an inductive plate load and a resonant circuit energized therefrom for producing a potential across one pair of thedeflection elements such as to cause the ray to produce an index trace, a circuit to produce oscillations of a given characteristic, potentiometer for efiecting utilization of a predetermined amplitude of the oscillations to cause the trace to traverse the screen at a uniform rate, means to modulate these oscillations, and a circuit for rectifying the modulated oscillations and applying corresponding direct current modulated potential across the other pair of deflection elements.

2. A' system for measuring elapsed time including a pair of cathode ray tubes each having an electron source, a screen and a pair of horizontal and vertical electron deflection plates; similar indicating scales correspondingly placed over said screens; a scanning system including a rotatable disc having irregular opaque portions, an exciter lamp, means for concentrating a beam of light on said disc and a photocell responsive to light penetrating said disc; connections for conveying a varying potential from the photocell to a grid controlled amplifier; only resistance in the oathode circuit of the last tube of said amplifier for reducing phase distortion in the output of said amplifier; an inductive plate load connected to the last tube of said amplifier; a resonant circuit energized from saidinductive load; said inductive load and resonant circuit serving to reduce frequency distortion and an impedance matching resistance connected intermediate said amplifier and a transmission line for controlling a vertical index trace on each cathode ray tube.

3. The system set forth in claim 2 including a deflection plate of the corresponding cathode ray tube.

ARTHUR H. DICKINSON. BIAGIO F. AMBROSIO.

REFERENCES CITED The following references are of record in the file of this patent:

} UNITED STATES PATENTS Number Name Date 1,882,684 Achard Oct. 18, 1932 1,966,696 Vincent July 17, 1934 2,088,478 Kovalsky July 27, 1937 2,283,103 1 Stuart May 12, 1942 2,301,197 Bradford Nov. 10, 1942 2,394,196 Morgan Feb. 5, 1946 2,397,032 Mestas Mar. 19, 1946 2,406,858 Shepherd Sept. 3, 1946 2,418,364 Moe Apr. 1, 1947 2,419,550 Hardy Apr. 29, 1947' 

